What is the definition of Augmented Reality and Virtual Reality?

// I'm asking this question in this forum because I believe this is the place where I have the highest chance of finding answer to my question, and I found no other sub-forums where my question would have fit better.

I am writing about augmented reality and I have a problem finding what is the definition of it or where can I find it. What I am looking for is a clear definition of what is augmented reality and what is virtual reality and what is the difference between the two.

What makes the problem harder is that since the last few years augmented reality have been used as (in my own words):

Looking at a marker or an object with a mobile device and having the camera's image displayed on the screen overlaid with objects in a 3D scene

However I believe this is not the real definition, just like how 3D screens shouldn't be called 3D but stereoscopic, but the PR folks turned it into 3D so now everyone calls them 3D.

For me, augmented reality would mean something where the user's coordinate system is registered to the virtual world's coordinate system, but while with virtual reality the user's natural environment is hidden or as-dark-as-possible, with augmented reality it is part of the user's perception, possibly because of a transparent screen or because the environment is simply visible around the virtual world.

Can you tell me where should I look for the original definitions (not Wikipedia, it's just as confused about AR as I am), or with your own words what would be the correct definitions?

Actually who invented these phrases and at what time? Was it invented by sci-fi writers in the 60s? Or by academics in the Silicon Graphics era?

Looking at a marker or an object with a mobile device and having the camera's image displayed on the screen overlaid with objects in a 3D scene

This is certainly a thing you can do with AR. Just like an FPS is a thing you can do with videogames. Both of these are pretty common AR/videogaming "tasks".

But they do not represent everything you can do with them.

not Wikipedia, it's just as confused about AR as I am

Wikipedia or no, the definitions seem pretty clear. They just doesn't agree with your definition:

For me, augmented reality would mean something where the user's coordinate system is registered to the virtual world's coordinate system, but while with virtual reality the user's natural environment is hidden or as-dark-as-possible, with augmented reality it is part of the user's perception, possibly because of a transparent screen or because the environment is simply visible around the virtual world.

No. Much like the example you provided, this is a thing you can do with AR. But it is not the sum total of it. AR does not have to be complex enough where there is a "virtual world" that you're superimposing on the real world.

AR is about taking a real-world image/scene and adding graphics to it, no matter how complex or how simple those additions are. It doesn't have to be applying graphics to a person in the real world; it could just be to a video stream, or even a static image. It's not something that has to be done to a person with eye-tracking gear or whatever, walking through a real-world area.

VR is centered around creating an entire world digitally. The two concepts are distinct.

Elements of AR include detecting where something is in the real world relative to a potentially virtual space, so that you can place a virtual object in that world. They include using the real world video stream to determine the location of the camera, perhaps relative to some marker of known position. And various other things. But these are all elements of AR; any particular use of AR can use some of them and not others, as they see fit.

In short, your definition is no better than the example you posted. The Wikipedia definition is correct, and it includes both.

Thank you for this answer Alfonse. But this way AR is an extremely wide concept, I mean even having a digital picture frame on a table is AR. Heck, even a painting on a wall is AR. Or a theatre with actors.

In this case I think my problem is that there are no distinct name for the 2 cases I mentioned, while these are very different and are used more and more today by being labeled as AR. And I think i'm not the only one who'd like to call the mixed-reality scenario I've described as AR, for example take a look at Michael Abrash's GDC talk from a couple of days ago:http://media.steampowered.com/apps/a...20GDC2013.pptx

Virtual reality, or VR, is when you’re immersed in a purely virtual world.
Playing Team Fortress 2 in an Oculus Rift would be VR.
Augmented reality, or AR, is when real reality, or RR, is enhanced with virtual images that appear to coexist with the real world.
Playing a game on a virtual chessboard that’s sitting on a real tabletop while wearing a see-through head mounted display would be AR.
Most of what I’ll say about VR today applies to AR as well.
The key commonality between VR and AR is that virtual images appear to exist in the same frame of reference as the real world.
So when you move your head, virtual images have to change correspondingly in order to appear to remain in the right place.
This tight association between the virtual world and the real world is how VR and AR differ from wearable information devices such as Google Glass. It’s far harder to keep the two worlds visually aligned than it is to just display heads-up information.

P.S: thanks for the amazing lm3dgp book, it's the best ever resource I found about learning 3D graphics!

Those don't use synthetic images. If it doesn't go through a computer in some way, it's not AR.

In this case I think my problem is that there are no distinct name for the 2 cases I mentioned, while these are very different and are used more and more today by being labeled as AR.

I don't really see the problem. AR is a broad field; there's no reason it shouldn't be broad. These two "very different" cases do have some common elements: the recognition of the real world and the location of some object(s) within it.

You're basically saying that it shouldn't be called "AR" unless it's big enough. I see no reason why you need to adopt the term "AR" for just that scenario. Especially when other scenarios are also augmenting reality.

If you want to invent a term for this particular use of AR, feel free. Granted, you're probably not going to get the rest of the world to go along with it, but you can. But you can't steal a term from people who are using it for what it is.

take a look at Michael Abrash's GDC talk from a couple of days ago:

Everyone likes for their field to have their own special name. Nobody likes being inclusive, especially if they see their stuff as being "far harder" than some lesser stuff.

That doesn't mean they're right.

I'm sure that the original researchers and builders of AI expert systems were non-plussed to find out that videogame developers started using much simpler AI heuristics. They're both still AI, and so is everything inbetween. They have had to invent terms for different categories of AI. But there's nothing wrong with that; they still have the general, overhanging term "AI" to mean "any of those things".

You're not going to get the more basic users of AR to stop using the term for their stuff. They have just as much right to it as the larger users of it. Best to get used to it.

OK, I got your points. So most importantly, it's not a misnomer like 3D TVs, but just a much wider category.

So - this is just my opinion - all the problem is that it's hard to communicate those categories without short and easy to remember names. For example, it's important to have words like multi-touch, or tablet or FPS, or HMD. Like in AI, it's actually a big problem that AI almost doesn't have any actual meaning, because it's so broad. So if you say your field is AI, you almost didn't say anything (same for computer science). I'm not saying that there is anything wrong with this, I'm saying that it's not efficient to talk about things without a good and short catchy name. Imagine if Kinect was "real-time rgb and depth point cloud acquisition device", or something similar. It became popular, and because it had a short and catchy name and it was alone in it's category, people started to call the category "Kinect" or "Kinect-like devices".

I couldn't be bothered to follow all the details of this few weeks old thread. "Virtual Reality" is synthetic display of a 3d environment to a user, always in first person perspective. It must have visual, but can include audio, tactile, or force feedback elements as well. "Augmented reality" is overlay of a virtual reality on a *real* environment. For instance in the VR approach, someone might interact with a model of an Abrams tank in some CAD program. In the AR approach, there would be an actual Abrams tank you're doing repairs on, with nice synthetic traces guiding what bolts you need to tighten up, maybe telling you the torque specs you're going to need in realtime.

Doesn't seem that confusing to me, but then, I went up the VR learning curve in the mid-90s.

All ARs are VRs. Not all VRs are ARs; in fact historically, most weren't. If the environment you're interacting with is totally synthetic, it's VR only.